Abstract
A new equilibrium diagram of the system Cobalt-Copper based on the results of the following methods has ben proposed: total, differential, as well as newly devised thermal analyses, magnetic and electrical measurements, dilatometry, microscopy and X-ray analysis. The results of the investigation are summerised as follows: (1) Primary crystallisation points lowers with the increase of Cu to the peritectic temperature 1112°, The compositions of β and γ solid solutions and liquid phase at the peritectic temperature are 12.8, 92 and 95.5% Cu respectively. (2) There is no monotectic reaction, that was suggested by Konstantinow; Co and Cu foam a homogeneous liquid in all mixtures. (3) The solidified alloys are composed one or two of the following three phases, i.e., α-Co, β-Co and y, the latter being the Cu-rich solid solution (4) The α-β allotropic transformation point of Co lowers with the increase of Cu, and at 10.2% Cu and 342° a eutectoid reaction occurs. (5) The lattice constant of a and S cobalt becomes larger with the addition of Cu, but the increasing amount is very small. The lattice constant of Cu-rich solid solution, on the contrary, becomes smaller with the addition of Co. (6) At room temperature the solubility of Cu in α-Co is 9.4%, while that of Coin Cu is 0.3% (7) The magnetic transformation point in S-Phase lowers with the addition of Cu down to 12.2% Cu and 1065°. (8) The X-ray analysis of an alloy of 95% Cu does not indicate any occurrence of peritectoid reaction, which was suggested by Sahmen. This fact was also confirmed by magnetic analysis.
